GPL Revisited.

Posted on: November 08, 2005

I have seen too many people, on too many occasions confusing what GPL is
about. Most common error is to think that one can not use a GPLed
product with a commercial application. More sophisticated version of the
confusion is some mumbling that involves the word "derivative" :-)

I think the root cause of the error is that 1) GPL License (as any legal
document) is obscure 2) GPL FAQ that is intended to remove the obscurity
is too long and it is hard to find the important piece within it. But
there is a
piece
that clarifies many things, stating:

Question: I just found out that a company has a copy of a GPL\'ed
program, and it costs money to get it. Aren\'t they violating the GPL
by not making it available on the Internet? \

Answer: No. The GPL does not require anyone to use the Internet for
distribution. It also does not require anyone in particular to
redistribute the program. And (outside of one special case), even if
someone does decide to redistribute the program sometimes, the GPL
doesn\'t say he has to distribute a copy to you in particular, or any
other person in particular.

What the GPL requires is that he must have the freedom to distribute a
copy to you if he wishes to. Once the copyright holder does
distribute a copy program to someone, that someone can then
redistribute the program to you, or to anyone else, as he sees fit.

What does this mean? GPL does not prohibit you to use your software,
of any license kind, with GPLed ones. Constraints only arise when you
decide to ship your software to third parties (which, if you are
developing a web application for own usage may never happen). GPL does
not require you to publish your code that you use with a GPLed
software, but it prevents you from denying others the right for
redistribution once you give them your code.

Bottomline: GPL prohibits you from prohibiting others, does not require
you to do anything in your own world.